1. Field of the Invention
The present invention relates to polyisocyanatoalkyl-phenyl-isocyanurates as well as a method for the preparation of these compounds and the use thereof as isocyanate components. The polyisocyanatoalkylphenyl-isocyanurates are compounds having novel structures and can be used as expandable materials, adhesives and resins for coating materials as well as starting materials therefor.
2. Description of the Prior Art
An example of polyisocyanato-isocyanurates which have conventionally been well-known is a isocyanurate of hexamethylene diisocyanate, represented by the following formula: ##STR2## This has been widely used in various fields as a resin for two-pack urethane coating materials as well as a starting material for the resin.
Saunders & Frisch, High Polymers, Vol. XVI, Polyurethanes: Chemistry and Technology II, Technology, p.453, proposes resins which comprise, as chief materials, alkyd resins, polyester polyols, acryl polyols or epoxy polyols and, as a hardening agent, an urethane type polyisocyanate derived from tolylene diisocyanate or an isocyanurate type polyisocyanate, as typical examples of the most general-purpose resins for two-pack urethane coating materials. These resins have been used not only in coating materials for furniture and woodworking, but also in coating materials for heavy duty anticorrosion so-called tar-urethane paints. However, urethane coating materials obtained from tolylene diisocyanate show substantially low weatherability.
In order to enhance the weatherability of these resins for coating materials, there have been proposed the use of urethane type polyisocyanates derived from hexamethylene diisocyanate (HDI) (see, for instance, Japanese Patent Publication for Opposition Purpose (hereunder referred to as "J.P. KOKOKU") No. Sho 45-11146); biuret type polyisocyanates type polyisocyanates (see, for instance, U.S. Pat. Nos. 3,487,080, 4,324,879 and 4,412,073); urethane-modified isocyanurate type urethane isocyanates (see, for instance, Japanese Patent Un-examined Publication (hereunder referred to as "J.P. KOKAI") No. Sho 57-47321 and U.S. Pat. No. 4,582,888). Specific examples of biuret type polyisocyanates are OLESTER NP1000 (available from MITSUI TOATSU CHEMICALS, INC.) and Desmodur N-75 (available from Sumitomo Bayer Co., Ltd.); specific examples of HDI isocyanurate type polyisocyanates are Sumidur N-3500 (available from Sumitomo Bayer Co., Ltd.) and CORONATE EH (available from NIPPON POLYURETHANE CO., LTD.). Organic plyisocyanates derived from an aliphatic or alicyclic compound such as isophorone diisocyanate (IPDI) or 4,4'-dicyclohexylmethane diisocyanate are also used. Specific examples of isocyanurate type polyisocyanates of IPDI include IPDI-T1890 (available from DAICEL-HUELS LTD.); and specific examples of IPDI urethane-modified polyisocyanates include IPDI-UT647 and IPDI-UT880 (available from DAICEL-HUELS LTD.). There have been used two-pack urethane coating materials which comprise these hardening agents and acryl polyols or polyester polyols as chief components.
These two-pack urethane coating materials are excellent in various properties such as weatherability, flexibility and wear resistance and secure an immovable position in, for instance, the repair of automobiles and facing of buildings and structures. However, they show insufficient drying characteristics. Therefore, they must be baked at a high temperature or must be allowed to stand for a long time period to obtain well-crosslinked tough coating material films therefrom.
As has been described above, conventional resins for two-pack urethane paints suffer from various drawbacks. For instance, tolylene diisocyanate type resins have high reactivity and hence are excellent in drying characteristics, but show substantially low weatherability, while aliphatic or alicyclic type resins are excellent in weatherability, but have unsatisfactory drying characteristics.
Moreover, it is unavoidable that, upon trifunctionalization by trimerizing diisocyanates or upon preparation of isocyanurate type polyisocyanates, pentamers or higher polymers are formed as by-products in addition to the intended trimers. In such cases, if the amount of these polymers is great, the resulting polyisocyanates have low compatibility with active hydrogen-containing compounds or solvents.
For the aforesaid reasons, it has long been desired to develop two-pack type urethane coating materials having excellent weatherability, drying characteristics and compatibility with, for instance, the foregoing active hydrogen-containing compounds or solvents.